Outboard motor assembly



Sem 22 mgl. L. J. JOHNSON ET AL ouTBoARD MOTOR ASSEMBLY Filed Jan. 28, 1929 3 Sheets-Sheet l MNHN, n www@ Z2 VWM@ MJJ f di@ Y HM W @p 22 93? L. J. JOHNSON 'E1-AL OUTBOARD MOTOR ASSEMBLY Filed Jan. 28, 1929 5 Sheets-Sheet 2 w MMM 00 5.. WNW Mw f JJ. 0W @H Z wm Hw Sept 22, E931. L. J. JOHNSON ET AL OUTBOARD MOTOR ASSEMBLY Filed Jan. 28, 1929 5 Sheets-Sheet 5 lill/4 lll/1111!;

Patented Sept. 22, 1931 UNITED STATES PATENTl OFFICE LOUIS J'. JOHNSON, 0F SOUTH BEND, INDIANA, AND HARRY L. JOHNSON, OF WAUKEGAN, ILLINOIS, ASSIGNORS TO JOHNSON BROTHERS ENGINEERING CORPORATION, OF

SOUTH BEND, INDIANA, A CORPORATION OF INDIANA y OUTBOABD MOTOR ASSEMBLY application 1aed January 2s, 1929. serial No. 335,447.

Our invention relates generally to marine internal combustion engines and particularly to marine motors of the outboard type having means for discharging exhaust gases underwater as also disclosed in our applications Serial No. 327,244 and Serial No. 374,110 and in Serial No. 380,730 of Louis J. Johnson.

It is in general one of the primary objects of our invention to provide an outboard motor which will operate quietly and which will prevent the accumulation of exhaust gases in the immediate vicinity of the motor and to this end our invention contemplates the provision of a motor with an improved underwater exhaust device of durable and practical construction.

Another object of our invention is to preclude the building up of deleterious back pressures within a motor of the above mentioned type and in order to accomplish this we propose to provide an efficiently operable relief mechanism which is automatically operable when variations in rotative speeds are experienced by the motor.

More specifically, it is an object of our present invention to provide an outboard motor with the above mentioned relief mechanism which is operatively connected with one of the manually operable speed control elements of the motor, whereby positive relief from the building up of back pressures is afforded when the engine is running at relatively low speeds.

Still another object of our invention is to provide an effective underwater exhaust mechanism for an outboard motor having a lower unit which is of substantial stream-line construction and we propose to effect the flischarge of exhaust gases from the stream-line housing'immediately below and at the rearward end of an anti-cavitation plate, thereby taking advantage of the suction created within the water at this point to expedite the withdrawal of' exhaust gases from the motor.

Another object of our invention is to provide an underwater exhaust mechanism comprising a passageway for directing exhaust.

gases away from the engine muler which is cooled by the circulation of water through eparate conduits positioned adjacent there- Still another object of our invention is to prevent the outer surface of the mufll'er of the motor from becoming heated and to accompllsh this we provide said muier with a acket through which cooling water may be continuously circulated.

These and other objects will be more app arent from the following detailed description when considered in connection with the accompanying drawings wherein Figure 1 is a central sectional view of an outboard motor embodying features of our invention, certain portions thereof being -shown in elevation and certain other structures such as the gasoline tank being removed for the purpose of disclosing parts otherwise hidden;

Figures 2 is a horizontal view of the mufller taken substantially along the line 2 2 of Figure 1;

Figure 3 is a horizontal transverse sectional view of the exhaust casin taken substantially along the line 3-3 of igure 1;

Figure 4 is a horizontal transverse sectional view of the cylindrical casing which surrounds the water circulating plpes and the engile drive shaft taken on line 4 4 of Figure Figure 5 is an elevational view of the outboard motor assembly as viewed from the left of Figure 1;

Figure 6 is a fragmentary transverse sectional view taken substantially along the line 6 6 of Figure 5 disclosing the shftable plate carried by the magneto structure for controllin the actuation of the relief valve;

igure 7 is an enlarged elevational view of the relief valve actuating device, the valve and associated casing being shown in section;

Fio'ure 8 is a side elevational view of said relief valve actuating device as viewed from the left of Figure 7 Figure 9 is a horizontal transverse sectional view of the lower stream-line unit taken substantially along the line 9-9 0f Figure 1;

Figure 10 is a transverse sectional view taken substantially along the line 10-10 of Figure 1;

Figure 11 is a similar transverse sectional view taken along the line 11-11 of Figure 1; Figure 12 is a transverse sectional view taken along the line 12-12 of Fi re 1;

Figure 13 is a section taken su stantially along the line 13-13 of Figure 1; an

Figure 14 is a transverse `section( taken along the line 14-14 of Figure 1.

Referring now to the drawings more 1n detail wherein like numerals have been employed to designate similar parts throughout the various figures, it will be observed that for the purpose of disclosing a practical application of our invention we have shown an outboard motor assembly of the opposed cylinder construction, said assembly comprising a pair of opposed cylinders 10 which are suitably mounted to opposite sides of a central crank case 12. The upper portion ofthis crank case 12 rotatably supports a flywheel 14 which houses the usual magneto structure (not shown in detail). This crank case 12 is mounted upon an annular head 16 (Figure 1) which is in turn secured in any suitable manner to the upper extremity of a cylindrical casing 18.

This casing 18 is rotatably mounted w1th1n a sleeve 20 which is pivotally mounted at 22 upon a bracket 24. This bracket 24 ma 'be of any conventional design of the type w ich is adapted for convenient application to the stern of a boat (not shown). It will thus be apparent that the engine proper together with the cylindrical caslng 18 1s rotatable about a substantially vertical axis within the sleeve or bearing 20 and also tiltable about the substantially horizontal axis 22.

The lower extremity of the sleeve 18 is formed with a flange 26 which is designed to receive and support a stream-line lower unit designated generally by the numeral 28. This lower unit 28 is preferably cast from alumin um or other suitable lmaterial and is secured 'against the lower surface of the flange 26 through the agency of a pair of elongated bolts 30 and a shorter bolt 32. These elongated bolts 30 extend through the casing 28 and are threaded into a propeller shaft housing 34. A shaft 36 mounted within the housing 34 supports a propeller 38 at its outer extremity and rotation is imparted to this shaft 36 by means of a bevel gear connection between this shaft and a vertical drive shaft 40 extendin upwardly through the casing 28. This sha 40 has a spline connection at its A upper extremity with the lower end of another drive shaft section 42, the upper extremity of which is operatively connected in any suitable manner with the engine crank shaft (not shown).

The casing 28 is of stream-line construction and in order to obtain a clear understanding of the stream-line structure as well as the arrangement of the various passageways within the unit or casing 28, reference is made to Figures 9 to 14 inclusive. It will be seen that the rotation of the propeller 38 will cause water to be forced through screening 44 in a water intake mouth 46 (Figures 1 and 11) upwardly into a passageway 48 (Figures 1 and 10) provided within the unit 28. From the passageway 48 the water will be-directed through a passageway 50 rovided in apipe 52 which extends upward y through the cylindrical casing 18. The upper extremity of this pipe 52 terminates within the annular tween the chamber 62 and a discharge -orifice 66 (Figures 1, 11 'and 12).

` It will be seen that a muier or what might be termed a combine manifold and muler 68 is secured to the rear side of the cylinders 10 as by means of suitable bolts 70. This mullerv 68 includes a cylindrical chamber 72 which communicates with the cylinders l0 by means of suitable passageways 74 (Figure 2) and the lower central portion of said muiller is formed with an openin 76 through which exhaust gasesI may pass into an exhaust passageway 78 which is enclosed within an elon gated casing 80. The mufller chamber 72 is enclosed within a casing provided with a water jacket 82 and water is supplied to this jacket from a passageway 84 (Figure 1) presented within a pipe 86 which is housed within the casing 80. The lower end of the casing 80 is supported within the rearwardly extending portion of the flan e 26.

The rearward portion o the stream-line casing or unit 28 is formed with a passageway 88 (Figures 1 and 10) which communicates at its upper extremity with the lower end of the passageway 78 provided within the casing 80. It will thus be apparent that exhaust gases from the muilier chamber 72 may pass downwardly through the assageway 78, into the passageway 88 and t en through a discharge orifice 90 into the water. Water circulation within the pipe 86 and the muiller water jacket 82 is occasioned through the actuation of the propeller 38 which causes water to be forced through a screened intake mouth 92 and upwardly through a passageway 94. This passageway 94 communicates with the passageway 84 within the pipe 86. Water is the exhaust passageway 78. The lower extremity of this water discharge passageway 98 terminates at a oint immediately above the rearward end ofp the flange 26.

IVe provide an anti-cavitation plate 91 (Figures 1, 5 and 9), the rearward extremity of which terminates immediately above the discharge opening 90. By havin the discharge opening 90 thus positione with respect to the anti-cavitation plate 91, we are able to take advantage of the partial vacuum or suction which is present in this vicinity when the motor assembly is being driven through the water at normal operating speeds. This suction is sufficient to greatly expedite the positive withdrawal of the exhaust gases from the muller and associated passageways and to insure the disposition of the exhaust gases below the surface of the water. In this manner the presence of exhaust gases in the vicinity of the motor assembly While in use is eliminated and the positive and continuous discharge of the gases into the water is insured.

In order to prevent the building up of back pressures by the exhaust gases we provide a relief mechanism designated generally by the numeral 100 which is shown in detail in Figures 6 to 8 inclusive. This relief mechanism comprises a suitable relief valve 102 which is pivotally mounted at 104 to the side of the casing 80. Resilient means such as a coil spring 106 is provided to normally urge said valve toward its closed position shown in lFigure 7. When the valve occupies this position exhaust gaseswithin the casing will pass uninterruptedly through the chamber 78 and will be discharged underwater. When said valve is open, these exhaust gases will be free to discharge into the atmosphere through an opening 108 provided in the casing 80 (Figure 7). The tendency for back pressures to be built up is obviously greater when the engine is running at low speeds and hence it is desirable to maintain the valve 102 open when the engine is operating under such slow speed conditions. In order to automatically open the valve 102 when the engine isfrunnin slowly, we have operatively connected sai chamber through a leverage system with one ofA the speed control elements such as the spark control handle 110 (Figure 1). This handle 110 is usually mounted upon a plate 112 which supports the magneto structures (not shown) and which is rotatable independently of the rotation of the iy-wheel 14. Secured beneath the rearward portion of the magneto plate 112 is a segment or plate 114. This plate is configurated along its inner margin as clearly shown in Figure 6. A finger 116 supported at the upper extremity of a pivoted arm 118 is maintained in engagement with the configurated edge of the plate or segment 114 by means of a coil spring 120 as clearly shown in Figures 6 and 8. Movement occasioned b the arm 118 is transmitted to the valve 102 ti'y means of an arm 122, a crank 124 and a bell crank 126. Thus when the finger 116 engages the serrated portion of the inner edge of the plate 114, as shown in Figure 6, the valve 102 will be closedbut when the plate is shifted to the left (Figurev 6) in response to the manual manipulation of the control handle 110, a cam portion 128 of the plate 114 will be moved agamst the linger 116 so as to e'ect the opening Vof the valve'102. When the plate 114 is shifted to the left in this manner and the edge portion 128 actuates the finger 116, the control handle 110, Figure 1, will occupy the position at which the ignition spark is retarded. When the finger 116 engages the serrated portion of the serrated edge of the plate 114, the ignition spark will be advanced. In other words, when the motor is running at speeds which are high enough to positively insure the discharge of exhaust gases into the water Without the development of back pressures, the valve l102 will remain closed. When the motor is running at slower speeds there is a much greater tendency for back pressures to be established and at this time the valve will auto matically be open. Obviously the valve 102 migh't be operatively connected with other speed control elements without departing from the spirit and scope of the present invention.

From the foregoing it will be observed that our invention contemplates the provision of an outboard motor assembly which is rotatable about a substantially vertical axis and which is tiltable about a zontal axis, the lower portion of said assembly being of Stream-line construction and having a gas discharge orifice positioned adjacent and to the rear of the propeller. By `discharging the gases at a point located to the rear of the propeller and immediately beneath the rearward portion of the anti-cavitation plate, said gases are positively withdrawn anddischarged beneath the water level. The relief mechanism provides a very effective means for relieving against the development of back pressures within the motor and further supplies a means which is operable in response to a speed control element or substantially horilever. Thus when the motor is slowed down to a speed at which the resistance of the water might be suiiicient to develop back pressures, the discharge passageway is opened to' the atmosphere, thereby permitting the free discharge of the gas above the waterlevel. By circulating the cooling water through the muiller jacket, said muiiler is prevented from becoming heated thereby eliminating the possibility of injury to an operator. The cooling water which is circulated through the mutller jacket not only prevents the heating of said mulller but also serves to cool the exhaust gases as they are being conducted from the mulller to the point of discharge beneath the water level.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is:

1. In an outboard motor assembly, the combination with a support, of a ymotor mounted thereon having a lower turnable unit, a drive shaft casing connecting the motor and said unit, an expansion chamber for receiving exhaust gases from the motor and means forming a passage way from the chamber to the unit separate from the casing, the lower unit having a. passage communicating therewith for discharging exhaust gases at the rear of the unit and below normal Water level.

2. In an outboard motor assembly, the combination with a support of water jacketed motor mounted thereon having allower turnable unit, a drive shaft casing connecting the motor and lower unit, an expansion chamber for receiving exhaust ases' from the motor havin a separate disc arge pipe extending there rom to the lower unit, the lower unit having adischarge passage for exhaust gases at the rear end below normal water level, and

means for circulating water through the drive sha-ft casing for cooling the motor.

3. In an outboard motor assembly, the combination with a support, of a motor mounted thereon having lower turnable unit, a drive shaft casing connectin the motor and the lower unit, means formmg a jacketed expansion chamber for receiving exhaust gases from the motor and a tubular passage extending from said chamber to the lower unit independent of the drive shaft casing, the lower unit having an exhaust passage communieating therewith and opening at the rear thereof below normal Water level, and means for circulating Water adjacent said passage way and through the expansion chamber water jacket.

4. In an outboard motor assembly, the combination with a support, of a water jacketed motor mounted thereon having a lower turnable unit, a casing extending between the moltor and the unit, means forming a 'aeketed exhaust chamber for receiving gases rom the motor, a separate casing extending from the expansion c amber to the lower unit and discharging exhaust gases at the, rear thereof, and means for circulating water from the lower unit separately to the Amotor water jacket and to the exhaust water jacket through the separate casings connecting them with the lower unit. i

5. In an outboard motor assembly, the combination with a support, of a water j acketed motor mounted thereon having a lower turnable unit, a drive shaft casing connecting the motor and lower unit, a drive shaft, propeller shaft and propeller connected to the motorand mounted in the lowervunit, a water jacketed exhaust chamber connected with the motor a separate casing extending from the chamber to the lower unit, the lower unit being of streamline cross section and having an integral anti-ca-vitation plate extending above the propeller, the lower unit vhaving a -passage connecting with the exhaustY casing to discharge ases below the plate at the rear of the pro e er, and means extending from the rear o the propeller and below the anticavitation plate in the lower unit for conveying cooling water in separate passages through the said casings to cool the motor and the exhaust chamber through the water jackets thereof respectively.

6. In an outboard motor assembly, the combination with a support having a pair of spaced parallel guide arms and a thrust plate, of a motor mounted thereon having a lower turnable unit, a drive shaft casing connecting the motor and the lower unit and rotatable in the support between the said guide arms in engagement with the thrust late, means forming an expansion chamber or receiving exhaust gases from the motor a casing extending from the chamber to the lower unit at a distance from the drive shaft casing to a1- low the latter to turn between the support arms without engaging the exhaust casing, the lower unit having a passage communicating with the exhaust caslng and discharging at the rear end of the unit. v

In witness whereof, we have hereunder subscribed our names.

LOUIS J. JOHNSON. HARRY L. JOHNSON. 

